Lithium with Sterling Alternator to Batteri Charger

[Bob666]

Got this unit:
https://sterling-power.com/products/alternator-to-battery-chargers-up-to-130a

Being offered:
https://batterygo.se/collections/litiumbatteri-12v-24v-fardigapaket/products/litiumbatteri-12v-202ah-lifepo4-paket-2

Knowing the Sterling can’t be configured for Lithium I thought I had to toss it and buy another gadget for separating the two battery banks.

However they mention an External Current Limiter.

What is that, where do I connect it (where in the charging chain) and what rating is appropriate?

Volvo Penta with old 50 A alternator.
Old battery charger 30 A, mounted in boat, activated with shore power.

Both these charging sources to same input ports on Sterling.

Sterling output feeds leisure bank AGM and lead-acid starting battery. Worked fine a couple of years and two Atlantic crossings.

Too lazy to change to much. Just fitting that current delimiter sounds fine!

There is also a huge solar panel on an arch, does most of the charging, hardly ever used shore power while cruising. The MPPT regulator can be reprogrammed for Lithium so no problem.

[Bob666]

https://youtu.be/ShtGB07fCSs

So we need a battery to battery charger? Where would I put it and please recommend products!

Should we also have another spare starting battery? What I would like to do is to have a handle, first you need to unlock it with a key, to avoid mistakes. In case of emergency if you need to start the engine you turn it and it:
A. Disconnect the Lithium bank from the engine
B. Connects the Start battery to the engine

This way you can start the engine in case of catastrophic failure on behalf of the lithium bank.

[Pete7]

Bob, the best you can have with a 50A alternator is probably one of these two DC to DC battery chargers:

https://sterling-power.com/collectio...nt=44923987541

https://www.12voltplanet.co.uk/victr...c-charger.html

The Sterling is a lot cheaper if you don't want Bluetooth connectivity. The down side is the programming buttons are a little clunky but you aren't going to be doing it very often so worth putting up with that for the cheaper price.

I am assuming that you will have the alternator charge the lead acid starting battery. If so then the above DC . DC charger will fit between the engine start battery and the LifePO4 battery. Also fit the 30A shorepower charger to the engine start battery.

Then and you said the Solar MPPT has a lithium setting connect the MPPT to the LifePO4 battery.

How old is the current AGM house bank and what is the plan with this? Do ask if you want to join the existing AGM and LifePO4 together in one house bank.

This I thought quite good as an introduction:

https://www.youtube.com/watch?v=2bNB...6SophieSailing

[Pete7]

Like you we have a good solar set up, but a 50A Volvo Penta alternator even with the Sterling A2B charger isn't really doing you any favours. Sell it to recoup some money and either use the standard alternator or replace the alternator with an uprated one which can still use the original belts.

Something like this is cost effective: https://www.startermotor-alternator-...73-15372-p.asp

Now in my post above I spec'd DC > DC chargers with a 30A rating because that is all you can hope to have with your 50A alternator. If you fit an new uprated alternator you could go to a DC > DC charger with say 60A or 2 x 30A chargers. Depends if you feel you need that extra charging from the alternator or if the solar panels will generate enough.

Pete

[RaymondR]

The External Current Limiter is probably just a resistance installed on the output of the alternator which causes the voltage regulator in the alternator to see a higher voltage and winds the alternator's current back.

I have used a SS bike spoke to do this when I charged the house bank with the engine alternator.

[olaf hart]

The Stirling unit has a separate low current output to the start battery, so probably not a good idea to use it as the first current source from the alternator to a DC to DC charger.
You probably need to use a lead battery in the house bank as the primary alternator connection, then DC to DC to Lithium from there, so,you get a decent alternator output.
You will also need a temperature sensor on the alternator to the Stirling.

[Flod]

Why can’t you keep your Sterling alt-Bat charger? I bought one of those when installing my lithium bank and it have performed flawless. There is a program for lifepo4 on it. I use the Sterling for:

1. Charging the start battery bank (lead acid)
2. Boosting and charging the lifepo4 bank
3. Temp control the alt and protect the alt from burning

Then I have the bms (123Bms) for controlling load/charge and other details for the lifepo4 bank

Works great. You could do the same I suppose

[sailinglegend]

I'm worried about your comment in Post #1

"Too lazy to change too much. Just fitting that current delimiter sounds fine!"

My advice would be that with this attitude you are not the right candidate to be installing Lithium batteries because they could burn a very big hole in your pocket without the right support systems.

You have AGMs and yet these should all have been installed 'as a system' to cope with the high current demands that they require - so you needed a bigger alternate with an external regulator with temperature sensors - much bigger multi-stage programmable charger - and a battery monitor so you can keep an eye on the state of the batteries.

Lithium batteries would then only need the charging profiles of the chargers to be tweaked.

So stay with AGMs and upgrade your systems - and charge the house batteries first.......

[olaf hart]

Originally Posted by Flod

Why can’t you keep your Sterling alt-Bat charger? I bought one of those when installing my lithium bank and it have performed flawless. There is a program for lifepo4 on it. I use the Sterling for:

1. Charging the start battery bank (lead acid)
2. Boosting and charging the lifepo4 bank
3. Temp control the alt and protect the alt from burning

Then I have the bms (123Bms) for controlling load/charge and other details for the lifepo4 bank

Works great. You could do the same I suppose

Sterling recommend an external current limiter if you use the AB chargers with lithium.
I contacted them last year and they suggested a BB charger.
Are you suggesting the BMS on the lithium battery works as an external current limiter?

https://sterling-power.com/products/...ers-up-to-130a

[Flod]

Originally Posted by olaf hart

Sterling recommend an external current limiter if you use the AB chargers with lithium.
I contacted them last year and they suggested a BB charger.

https://sterling-power.com/products/...ers-up-to-130a

Ok but at least in my use case a “current limiter” is not needed. This is combat proven in the real world. I think that Sterling recommends this to have their back free if someone toasts their alt. In my case I have 80A alt (standard hitachi) and a 200ah lifepo4 bank.

[olaf hart]

Originally Posted by Flod

Ok but at least in my use case a “current limiter” is not needed. This is combat proven in the real world. I think that Sterling recommends this to have their back free if someone toasts their alt. In my case I have 80A alt (standard hitachi) and a 200ah lifepo4 bank.

Nice to know, I am considering adding a single 100AH lithium battery alongside my AGM house bank, plan is to cycle it first and use the AGM’s as a backup.
I was going to use a DC to DC charger between the different battery types to protect the AB charger, but sounds like it’s not necessary.
Alternator is a heavy duty 80 amp unit with a temp sensor.

[Flod]

Originally Posted by olaf hart

Nice to know, I am considering adding a single 100AH lithium battery alongside my AGM house bank, plan is to cycle it first and use the AGM’s as a backup.

I was going to use a DC to DC charger between the different battery types to protect the AB charger, but sounds like it’s not necessary.

Alternator is a heavy duty 80 amp unit with a temp sensor.

Yes what happens in my setup is that when the alt is getting to hot (this normally occurs after like an hour of running) the temp sensor on the alt from the Sterling reduces the current from 55-66A down to 15-20A. No extra current limiter needed.

[RaymondR]

The fans on alternators are not particularly efficient and we tend to run the alternators at relatively slow speeds. You could mount a small 12 C DC electric fan on the back end to help cooling.